Fuel cells can convert suitable hydrogen or hydrocarbon fuels directly into electrical power. As such, fuel cells have promise as a source of clean energy. Fuel cells have been proposed as power sources for devices as diverse as automobiles, personal computers and flashlights. Fuel cells are typically arranged in stacks. A stack configuration provides a maximized volumetric power density. The fuel cells in a typical stack each have a membrane electrode assembly (MEA). Flow field plates are located on either side of the MEA. The flow field plates are typically rigid. The flow field plates provide channels by way of which fuel and an oxidant are supplied to opposing sides of the MEA.
A fuel cells stack may be configured to fit in place of a battery. Some fuel cell stacks are cylindrical. Conventional designs require a device to be powered by a fuel cell stack to provide space to accommodate the fuel cell stack and its accompanying fuel storage container.
For large stationary devices, the volume requirements of conventional fuel cell stacks is relatively inconsequential. However, in portable applications, space is at a premium. In order to maximize power to the device, the active area of the stack must be large. In order to maximize operational lifetime, the volume available for fuel storage must be maximized. Current portable fuel-cell-powered devices are designed around the space required by the fuel cells and fuel storage just like their battery-powered counterparts are designed around the space required by batteries. This has typically resulted in undesirably bulky devices.
U.S. Pat. No. 6,131,851 to Williams describes vehicles which have an energy generating skin as an outer covering. The skin may be a fuel cell. U.S. Pat. No. 5,759,712 to Hockaday, describes a fuel cell stack that is wrapped around a fuel storage cylinder. U.S. Pat. No. 6,620,542 to Pan discloses a flexible substrate based fuel cell.
There exists a need for practical and convenient fuel-cell-powered devices.